Body building and physical fitness equipment employ a variety of forms. All of which are adapted to provide resistance to user muscle exertion, exercise, and to build muscle tissue during an exercise regime. In recent years, weight “machines” have become popular as they can be configured to provide a plurality of positions and exercises at different stations or configurations of the machine. In each exercise, a cable running a serpentine route communicates resistance from weights to the component being pushed, pulled, or lifted by the user. A plethora of weight selection module systems have been developed with such machines. All in an attempt to allow a user to variably select an aggregate weight using a group of weights which are operatively engaged to the distal end of the cable and are employed to provide resistance for each workout. Users conventionally choose a weight combination to yield the aggregate amount of weight resistance based on their individual strength, exercise routine, and workout tactics.
Weight lifting machines are often composed of two mating and interchangeable components. First, a resistance module provides the exercise load to provide resistance to the user movement during exercise. A second component interface provides the operative engagement of one or a plurality of weights with the cable and enables the user to apply a determinable force to the station or machine to exercise a defined muscle or muscle group.
Employing the conventional weight stack resistance module, as seen in U.S. Pat. No. 7,871,357, a user typically selects their desired lifting load, by inserting a pin through a vertical rod, which communicates through one of multiple layers of metallic plates. A positioning of the pin in a particular point on the rod causes the engaged plate to support overhead plates when elevated and thereby determines the aggregate amount of weight engaged to the cable from the plurality of weight plates selected through placement of the pin.
Generally, the weight plates each contain at least one or a plurality of bore holes positioned to guide the plates during translation on aligned rods communicating through the bore holes. One through-bore hole communicates vertically through a central portion of the thickness of the plates between the top surface to the bottom surface. In use, this centrally located bore hole surrounds an inserted translating vertical rod. This rod, along with any supported weight plates in operative engagement, translates along a vertical path when moved by a user gripped or engaged exercise. The weight of the engaged weight plates, thus, provide the resistance to movement of the interfacing component by the user, such as a barbell type component or the like.
Conventionally, a pair of outer through-bore holes, which lie symmetric about the centrally located hole in each weight plate, are slidably engaged about vertically inclined support bars which, during use, constrain the weight plates from rotating. An engagement aperture conventionally communicates horizontally through the width of each weight plate between the top and bottom surfaces and intersects the middle through-bore.
Rod apertures communicating into the translating vertical rod, sequentially spaced to be aligned with a complimentary spacing of the engagement apertures running through each weight plate when positioned in a stack. To choose a resistive load for use with any particular exercise component using the weight stack for resistance, a pin is user-engageable through any single engagement aperture to also engage a rod aperture in the vertical translating rod. Thus, the user, by engaging the bottom weight in the stack to the rod, will have a resistance weight of all the weights in the stack when the vertical rod translates. The resistance weight may be adjusted by engaging the pin through the engagement aperture of a weight plate higher in the stack and vice versa. However, this system has a number of shortcomings.
First, as noted, the system employs a selector pin which must be moved to different engagement apertures of differently positioned weight plates in the stack. As with any loose engagement device, the selector pin is easily lost if it is not tethered to the machine. Should the tether fail, the selector pin, in a gym environment with many different users, tends to become lost or is moved to other weight stacks which also have lost selector pins. Additionally, the pin can become worn and hard to insert.
Further, in a commercial gym environment misuse of the weight system through improper selector pin insertion or mis-engagement can bend the selector pin. In either case a damaged or lost selector pin can cripple the entire machine engaged to a particular weight stack.
Other problems can occur over time, even where the selector pin remains proximate to a weight stack and used property. Because the translating rod engaging the weight stack is frequently engaged to a cable which tends to elongate over repeated use to lift the load of weights engaged to the rod, misalignment frequently occurs between the engagement apertures in the weight plates, and the translating vertical rod. Such can make it difficult if not impossible to properly position the selector pin through a chosen weight plate and aperture in the translating rod. This can disable the exercise machine engaged to the weight stack, or at least make it irksome and more time consuming to use.
Other issues exist with conventional weight stack engaged exercise machines which, while not mechanically impairing the operation of the machine, can be annoying and even injurious to the user. During translation of the weight stack during use from a stack-supported position and back, the metal weight plates contact each other and cause significant noise and over time significant wear. Additionally, a significant risk of injury is always present during use of weight stack resistance exercise machines. This is because a pinch point exists between the lowest weight in the plurality lifted by rod translation and the weight plate upon which the translating stack lands. The pinch point can cause severe injury to the user of the exercise machine, or more often, to a third party who places a digit between the non moving weight and the weight stack being lowered by translation of the rod downward.
Several advancements have been made to reduce the inadequacies of the pin and weight stack system, such as the leverage-weight machines. Leverage weight machines allow the user to adjust the mechanical advantage to tune a static load, providing the user-chosen resistance without removable pins. This has proven much easier and safer for users by eliminating the use of an external pin altogether and reducing dangerous pinch points, and potential poor pin engagement which can cause raised stacks of weights to release.
Leverage machines are based on the principal that increasing or decreasing the applied moment arm through which the user lifts a given constrained weight, increases or decreases the work required by the body of the user and thus increases or decreases the resistance to movement. Thus, the force necessary to perform the exercise by the user may be increased or decreased.
In an example of a leverage weight machine, U.S. Pat. No. 5,263,914 allows the user to adjust the mechanical advantage by employment of a system of pulleys and cables which lift a singular or static amount of weight. U.S. Pat. Nos. 7,537,552 and 8,323,158 employ a similar technique by replacing the weight-based load source with biasing sprung bands and resistive pneumatics respectively.
While these current leverage style weight machines reduce the need for a variable weight stack and engaging pin, such leverage systems employ a complicated pulley arrangement and serpentine cabling system, along with a multitude of moving parts inherent to such complicated designs. The employment of numerous cables, rotating pulleys, and other moving parts frequently renders such machines noisy, costly, difficult to maintain. Further, the presence of numerous cables running over numerous pulleys increases injury potential through the formation of numerous potential pinch points of the cables and pulleys. Unlike weight stack pinch points, users unfamiliar with cable and pulley operation are frequently unaware of the potential for injury.
As such, there is an unmet need for a resistive weight apparatus which alleviates the shortcomings of prior art weight resistive devices. Such a device should be simple to manufacture, build and maintain to thereby reduce costs and encourage widespread sales to encourage users to exercise. Such a system should be constructed with an arrangement of components which render it quiet, which would be especially helpful in a gym environment with multiple concurrent users of multiple exercise machines. Ideally, the potential for injury should be reduced by eliminating or reducing the number of potential pinch points in the device and system. Further, unlike the current pin and weight stack systems, which locate the weight stack a distance from the engaged exercise device and generally near the floor, such a device should include a means for user choice of resistance which is easily viewed and which allows the user to easily and quickly calculate, and adjust the desired resistance load yielded for their particular exercise routine. Further, unlike conventional cable and pulley systems and weight stacks which require a considerable amount of floor space due to their configuration, such a device should ideally allow for use in a small footprint of floor space.
The forgoing examples of related art and limitation related therewith are intended to be illustrative and not exclusive, and they do not imply any limitations on the invention described and claimed herein. Various limitations of the related art will become apparent to those skilled in the art upon a reading and understanding of the specification below and the accompanying drawings.